Zutao Ouyang

Zutao Ouyang
Stanford University | SU · Earth System Science

PhD - Geography

About

92
Publications
28,357
Reads
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2,309
Citations
Additional affiliations
June 2019 - present
Stanford University
Position
  • PostDoc Position
November 2015 - May 2019
Michigan State University
Position
  • Research Associate
August 2010 - July 2011
Fudan University
Position
  • Research Assistant
Education
August 2014 - July 2015
Michigan State University
Field of study
  • Geography
September 2011 - May 2014
University of Toledo
Field of study
  • Ecology
June 2007 - July 2010
Fudan University
Field of study
  • Ecology

Publications

Publications (92)
Article
Object-oriented classification (OOC) has shown many significant advantages over other methods for classification of urban or forest ecosystems. However, it remains unclear if this technology could exhibit these advantages on mapping monospecific plant stands in herbaceous plant dominated ecosystems (e.g. saltmarshes). In this study, we compared the...
Article
Urban built-up area, one of the most important measures of an urban landscape, is an essential variable for understanding ecological and socioeconomic processes in urban systems. With an interest in urban development in transitional economies in Southeast Asia, we recognized a lack of high-to-medium resolution (<60 m) built-up information for count...
Article
Full-text available
Lakes are important components for regulating carbon cycling within landscapes. Most lakes are regarded as CO 2 sources to the atmosphere, except for a few eutrophic ones. Algal blooms are common phenomena in many eutrophic lakes and can cause many environmental stresses, yet their effects on the net exchange of CO 2 (F CO2) at large spatial scales...
Article
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The replacement of natural lands with urban structures has multiple environmental consequences , yet little is known about the magnitude and extent of albedo-induced warming contributions from urbanization at the global scale in the past and future. Here, we apply an empirical approach to quantify the climate effects of past urbanization and future...
Preprint
Full-text available
Reducing methane emissions is essential for mitigating global warming. To attribute methane emissions to their sources, a comprehensive dataset of methane source infrastructure is necessary. Recent advancements with deep learning on remotely sensed imagery have the potential to identify the locations and characteristics of methane sources, but ther...
Article
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An emerging and pressing issue in China’s economic reform is the intensified conflict between arable land protection and the encroachment of urban development into fertile farmlands that threaten food security and urban sustainability. New policies were issued to encourage rural land circulation as an attempt to ensure urban development and a susta...
Article
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Hydropower dams produce huge impacts on renewable energy production, water resources, and economic development, particularly in the Global South, where accelerated dam construction has made it a global hotspot. We do not fully understand the multiple impacts that dams have in the nearby areas from a global perspective, including the spatial differe...
Article
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This paper synthesizes the contemporary challenges for the sustainability of the social-environmental system (SES) across a geographically, environmentally, and geopolitically diverse region – the Asian Drylands Belt (ADB). This region includes 18 political entities, covering 10.3% of global land area and 30% of total global drylands. At the presen...
Article
Natural gas stoves in >40 million U.S. residences release methane (CH4)─a potent greenhouse gas─through post-meter leaks and incomplete combustion. We quantified methane released in 53 homes during all phases of stove use: steady-state-off (appliance not in use), steady-state-on (during combustion), and transitory periods of ignition and extinguish...
Article
Time series of wetland methane fluxes measured by eddy covariance require gap-filling to estimate daily, seasonal , and annual emissions. Gap-filling methane fluxes is challenging because of high variability and complex responses to multiple drivers. To date, there is no widely established gap-filling standard for wetland methane fluxes, with regar...
Article
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Integrating the dynamics and interconnections of natural and human system properties into a single measure would make it simpler to reliably and repeatedly assess and compare different social-environmental systems (SES). We propose a novel metric to assess the magnitudes and variations in SES dynamics by integrating longitudinal gross domestic prod...
Article
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Surface albedo is an important forcing parameter that drives the radiative energy budget as it determines the fraction of the downwelling solar irradiance that the surface reflects. Here we report on ground-based measurements of the spectral albedo (350–2200 nm) carried out at 20 sites across a North–South transect of approximately 1300 km in the A...
Article
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Methane (CH4) emissions from natural landscapes constitute roughly half of global CH4 contributions to the atmosphere, yet large uncertainties remain in the absolute magnitude and the seasonality of emission quantities and drivers. Eddy covariance (EC) measurements of CH4 flux are ideal for constraining ecosystem-scale CH4 emissions due to quasi-co...
Article
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Large datasets of greenhouse gas and energy surface-atmosphere fluxes measured with the eddy-covariance technique (e.g., FLUXNET2015, AmeriFlux BASE) are widely used to benchmark models and remote-sensing products. This study addresses one of the major challenges facing model-data integration: To what spatial extent do flux measurements taken at in...
Article
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While wetlands are the largest natural source of methane (CH4) to the atmosphere, they represent a large source of uncertainty in the global CH4 budget due to the complex biogeochemical controls on CH4 dynamics. Here we present, to our knowledge, the first multi‐site synthesis of how predictors of freshwater wetland CH4 fluxes (FCH4) vary across we...
Article
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Cultural heritage sites and landscapes are intuitively connected in urban systems. Based on available databases of cultural landmarks, we selected three pairs of cities that are currently dominated by three contrasting religions (Catholic, Buddhist and emerging culture) to compare the long-term changes in cultural landmarks, to quantify their spati...
Article
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Producing gridded electric power consumption (EPC) maps at a fine geographic scale is critical for rational deployment and effective utilization of electric power resources. Brightness of nighttime light (NTL) has been extensively adopted to evaluate the spatial patterns of EPC at multiple geographical scales. However, the blooming effect and satur...
Preprint
Full-text available
Methane (CH4) emissions from natural landscapes constitute roughly half of global CH4 contributions to the atmosphere, yet large uncertainties remain in the absolute magnitude and the seasonality of emission quantities and drivers. Eddy covariance (EC) measurements of CH4 flux are ideal for constraining ecosystem-scale CH4 emissions, including thei...
Article
Nighttime light imageries are widely used for mapping the gross domestic product (GDP) over large areas. However, nighttime light imagery is inappropriate to disaggregate agricultural GDP and inadequate to differentiate the GDP from the secondary and tertiary sectors. Points-of-interest, a kind of geospatial big data with geographic locations and t...
Article
Rapid urbanization and industrialization in China stimulated the great increase of energy consumption, which leads to drastic rise in the emission of anthropogenic waste heat. Anthropogenic heat emission (AHE) is a crucial component of urban energy budget and has direct implications for investigating urban climate and environment. However, reliable...
Article
Full-text available
To examine the spatial patterns of hydrological variations in the southern and northern East Asia Monsoonal (EAM) region on millennial time scales, as well as to investigate the relationship between hydrological changes and carbon accumulation in these regions with contrasting environmental backgrounds, we performed facies-based hydrological recons...
Article
Full-text available
ContextAlbedo can be used to quantify ecosystem and landscape contributions to local and global climate. Such contributions are conventionally expressed as radiative forcing (RF) and global warming impact (GWI). We contextualize our results within landscape carbon production and storage to highlight the importance of changes in albedo for landscape...
Article
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Lateral movements of materials and energy in coastal wetlands, due mainly to tidal activities, have been recognized as key processes in understanding the biogeochemical cycles of ecosystems. However, our understanding of the roles of lateral movement in shaping ecosystem functions remains limited. Here we quantified the effects of lateral sediment...
Chapter
The drylands region of Northwest China is an extensive, vulnerable environment and has experienced dynamic migration patterns along with dramatic urban expansion in the past six decades. This chapter assesses migration and urbanization of this region from the middle of the twentieth century until 2015, with a particular focus on the period followin...
Chapter
Full-text available
In this chapter, we provide an overview of the social-ecological systems (SES) in the Asian Drylands Belt (ADB), a vast geographical region composed of 17 independent countries and six administrative provinces of China. The ADB, which covers 15.4 million km² and is the home to more than 645 million people, has served as a major human migratory rout...
Article
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Context The open and free access to Landsat and MODIS products have greatly promoted scientific investigations on spatiotemporal change in land mosaics and ecosystem functions at landscape to regional scales. Unfortunately, there is a major mismatch in spatial resolution between MODIS products at coarser resolution (≥ 250 m) and landscape structure...
Article
The construction of transportation corridors (such as roads) frequently disturbs and alters the natural disturbance regimes of ecosystems in many areas worldwide. In this study, by comparing the species richness, diversity, composition and soil among four ecotypes (non-road disturbance areas, road systems without ditches, road systems with large an...
Article
Ecological restoration programs (ERPs) have been conducted in China since 2000 to improve ecological conditions, particularly in the farming-pastoral ecotone of Northern China. Few have studied the effects of ERPs on landscape structure. Taking West Liaohe River Basin (WLRB) as a case study, we explored how landscape dynamics were altered before an...
Article
Full-text available
This paper proposes a framework for measuring compactness and urban green accessibility in a high-density transit-oriented metropolis and uses Taipei City and its surrounding outskirts, New Taipei City, as a case to illustrate the measurement framework. Two indices, urban compactness index (UCI) and urban green accessibility index (UGAI), are devel...
Article
Ulaanbaatar, the capital of Mongolia, has experienced unprecedented urbanization following the collapse of the Soviet Union. Lack in housing supply has led to an expansion of informal settlements, mostly in the form of Gers-portable tents used by nomads in Mongolian Plateau. These settlements now host approximately 45% of Ulaanbaatar's total popula...
Article
The biomass of the subtropical forests of China is an important component of the global carbon cycle. Recently, several above ground biomass (AGB) maps have been produced using a variety of approaches to assess the carbon stock of the subtropical forest in China. However, due to the lack of reliable ground observations and the limitations of AGB ma...
Article
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The Pearl River Delta (PRD) is one of the most important economic zones both in China and in the world. Its rapid economic development has been associated with many environmental problems such as the loss of forests in urban areas. We estimated the accessibility of forests in the PRD by quantifying spatial proximity and travel time. We found that d...
Article
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Introduction The effects of nutrients on stream conditions within individual streams or small areas have been studied extensively, but the same effects over a large region have rarely been examined due to the difficulty of applying large-scale manipulative experiments. In this study, we estimated the causal effects of nutrients within the Western U...
Article
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The Mongolian Plateau hosts two different governments: the Mongolian People's Republic and the Inner Mongolia Autonomous Region, a provincial-level government of the People's Republic of China. The divergence between these governments has widened in the past century, mostly due to a series of institutional changes that generated different socioecon...
Article
Remote sensing image products (e.g. brightness of nighttime lights and land cover/land use types) have been widely used to disaggregate census data to produce gridded population maps for large geographic areas. The advent of the geospatial big data revolution has created additional opportunities to map population distributions at fine resolutions w...
Article
We used the experiences of Vietnam following the economic reform, known as Doimoi, to study urbanization, economic development, and environmental and social changes in transitional economies at multi-scales. The country underwent rapid urban land expansion, as indicated by the increase in the mean value of nighttime light data from −1.4 in 1992 to...
Article
Flux measurements based on aerodynamic principles (e.g., eddy covariance method, or EC) assume the vegetation and landform within the footprint must be flat, large, and homogeneous, although very rarely do flux tower sites meet such requirements. Here, using two long term EC tower sites in Mongolian grasslands, we test a hypothesis that the magnitu...
Article
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Spanning a vast territory of approximately 13 million km², Asian Russia was home to 38 million people in 2016. In an effort to synthesize data and knowledge regarding urbanization and sustainable development in Asian Russia in the context of socioeconomic transformation following the breakup of the Soviet Union in 1990, we quantified the spatiotemp...
Article
Global distribution of urban lands is one of the essential pieces of information necessary for urban planning. However, large disagreement exists among different products and the uncertainty remains difficult to quantify. We applied a Bayesian approach to map the uncertainties of global urban lands. We demonstrated the approach by producing a hybri...
Article
Built-up area has become an important indicator for studying urban environments, but mapping built-up area at the regional/global scale remains challenging due to the complexity of impervious surface features. Nighttime light data (NTL) is one of the major remote sensing data sources for regional/global built-up or impervious surface mapping. A sin...
Article
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Lakes are active processors of organic carbon (OC) and play important roles in landscape and global carbon cycling. Allochthonous OC loads from the landscape, along with autochthonous OC loads from primary production , are mineralized in lakes, buried in lake sediments, and exported via surface or groundwater outflows. Although these processes prov...
Article
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Urban expansion has long been a research hotspot and is often based on individual cities, but rarely has research conducted a comprehensive comparison between coastal and inland metropoles for understanding different spatial patterns of urban expansions and driving forces. We selected coastal metropoles (Shanghai and Shenzhen in China, and Ho Chi M...
Article
Temperate and semiarid grasslands comprise 80% of the land area on the Mongolian Plateau and environs, which includes Mongolia (MG), and the province of Inner Mongolia (IM), China. Substantial land cover/use change in the last few decades, driven by a combination of post-liberalization socioeconomic changes and extreme climatic events, has degraded...
Article
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The lateral transport of carbon has been increasingly recognized as an important component of carbon budget in wetlands. We studied a typical coastal salt marsh located at the estuary of the Yangtze River by measuring lateral transfer of macro-detritus carbon within a creek during each month’s largest spring tide period, and simultaneously, we meas...
Article
Aims Riparian ecosystems play an important role in overall ecosystem function, including the global carbon cycle of terrestrial ecosystems, at both landscape and global scales. Yet few studies have reported in situ measurements of CO 2 in riparian areas where flooding is a unique disturbance to carbon cycling. Methods At multiple locations across r...
Article
Full-text available
CH4 emissions could vary with biotic and abiotic factors at different time scales. However, little is known about temporal dynamics of CH4 flux and its controls in coastal marshes. In this study, CH4 flux was continuously measured with the eddy covariance technique for 2 years in a subtropical salt marsh in eastern China. Wavelet analysis was appli...
Article
Background: Quantifying carbon (C) dioxide exchanges between ecosystems and the atmosphere and the underlying mechanism of biophysical regulations under similar environmental conditions is critical for an accurate understanding of C budgets and ecosystem functions. Methods: For the first time, a cluster of four eddy covariance towers were set up...
Article
Water body mapping is an important application of optical remote sensing. Methods for classifying water bodies using multispectral image data have been successfully developed for water resource monitoring and management. However, in most cases, these traditional methods provide only partial automation capabilities. In this study, we propose a new s...
Article
Urban sprawl presents a serious challenge for sustainable urban land use. Urban planning attempts to guarantee sustainable urban development and proper use of land resources. However, a large gap usually exists between planning and actual development. This paper aims to analyze the evolutionary characteristics of urban form and the spatiotemporal d...
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Full-text available
The highest densities of lakes on Earth are in north temperate ecosystems, where increasing urbanization and associated chloride runoff can salinize freshwaters and threaten lake water quality and the many ecosystem services lakes provide. However, the extent to which lake salinity may be changing at broad spatial scales remains unknown, leading us...
Article
Using Barcelona and Shanghai as case studies, we examined the nature-based solutions (NBS) in urban settings-specifically within cities experiencing post-industrialization and globalization. Our specific research questions are: (1) What are the spatiotemporal changes in urban built-up land and green space in Barcelona and Shanghai? (2) What are the...
Article
Aims: Riparian ecosystems play an important role in overall ecosystem function, including the global carbon cycle of terrestrial ecosystems, at both landscape and global scales. Yet few studies have reported in situ measurements of CO2 in riparian areas where flooding is a unique disturbance to carbon cycling. Methods At multiple locations across r...
Article
Full-text available
Previous studies have concluded that the increase in vegetation in the arid northwest of China is related to precipitation rather than temperature. However, these studies neglected the effects of climate warming on water availability that arise through changes in the melting characteristics of this snowy and glaciated region. Here, we characterized...